The present invention relates to a suction muffer for a hermetic reciprocating compressor.
A hermetic compressor is generally employed in a cooling system such as a refrigerator or an air conditioner, so as to compress a gaseous refrigerant from an evaporator and supply the compressed refrigerant to a condenser.
A rotary-type or reciprocating-type compressor is generally used for the hermetic compressor. The reciprocating hermetic compressor includes a suction muffler for a stable supply of a refrigerant to be compressed to a reciprocating compressing portion thereof. The suction muffler temporarily contains the refrigerant which is supplied from outside to be compressed and supplies the refrigerant to the compressing portion through a cylinder head of the reciprocating compressing portion.
FIG. 3 shows a sectional view of a conventional suction muffler for a hermetic reciprocating compressor. As shown in FIG. 3, a suction muffler 40 includes a muffler body 45 forming a containing space 56 for a gaseous refrigerant to be compressed. The suction muffler 40 is provided with a refrigerant inlet 47 which is connected with an external refrigerant supplying pipe 37 and a connection pipe 34 which is connected with a suction port 33 formed in a cylinder head 32 of a compressing portion 31 and serves as a refrigerant outlet. A tubular baffle 51 which extends towards the containing space 56 from the connection pipe 34 is provided inside the muffler body 45. The baffle 51 is supported by a supporting wall 41 which is provided inside the muffler body 45.
The refrigerant is supplied to the refrigerant inlet 47 through the refrigerant supplying pipe 37 and temporarily contained in the containing space 56 of the muffler body 45. Then, the refrigerant flows through the baffle 51 and the connection pipe 34 and is supplied to the compressing portion 31 through the suction port 33 formed in the cylinder head 32 of the compressing portion 31, during a suction stroke of the compressing portion 31.
However, in the hermetic reciprocating compressor, a pulsatory noise with a relatively low frequency due to suction and compression operations and a noise with a relatively high frequency due to opening and closing of suction and discharge valves are generated, during suction and compression strokes. These noises go backwards with respect to the flowing direction of the refrigerant and are transmitted outside through the suction muffler 40 and the inside of a casing of the compressor.
The noises which are transmitted to the suction muffler 40 from the compressing portion 31 are damped by resonance or mutual cancelling while being transmitted and reflected in a variety of directions inside the containing space 56 of the suction muffler 40. The noises which are damped inside the suction muffler 40 forming a resonance box are noise components having frequencies corresponding to values obtained by dividing four times of a resonance length or a resonance depth, along which the noises are reflected, by the velocity of a sound wave.
However, the containing space 56 of the conventional suction muffler 40 provides relatively simple transmission paths of noises, noises having specific frequency ranges are relatively effectively damped, whereas noises having various frequency ranges can not be effectively damped.